The present invention relates to packingless gate valves and more particularly to a knife gate valve having pipe nipples extending from each end of the valve body for use in attachment of the valve to the piping system and with a specific construction of internal components including an elastomer sleeve with stiffener ring mounted in a lock ring so as to result in improved operation in sealing of the gate. The valve of the present invention may be used for any of various fluid control operations.
The gate valve of the present invention is an improvement of the gate valves as described in previous Clarkson patents, including U.S. Pat. Nos. 3,945,604; 4,007,911; 4,257,447; and 4,688,597.
The present invention provides an improved construction as compared to the gate valves of the previous patents by a special arrangement of the sleeve structure and stiffener ring mounted in a lock ring at opposite sides of the gate having novel coaction with the gate and mounted in a novel manner in the valve housing.
Accordingly, it is an object of the present invention to provide a novel gate valve assembly wherein resilient sleeve units at opposite sides of the gate are mounted in a special manner in the valve housing and have special coaction with the relatively slidable gate.
A further object of the invention is to provide a novel gate valve assembly wherein the inner ends of axially compressed sleeve units engage opposite sides of the gate in the valve closed condition and sealingly engage in the valve opening condition, and are of special structure as mounted in a lock ring installed in each housing half so as to provide improved coaction between the sleeve units and the gate.
Another object of the invention is to provide a novel gate valve assembly wherein each sleeve end at the gate is of a specific configuration and with a lock ring of novel construction and location being provided to maintain the sleeve in position when the gate is opening or closing.
Another object of the invention is to provide a novel gate valve assembly wherein opposed sleeve units under axial compression are coaxially mounted in a novel manner in a valve housing.
Further objects of the invention will be apparent from the following description as taken with the appended claims and the accompanying drawings.